- Re-implement lock profiling in such a way that it no longer breaks

   the ABI when enabled.  There is no longer an embedded lock_profile_object
   in each lock.  Instead a list of lock_profile_objects is kept per-thread
   for each lock it may own.  The cnt_hold statistic is now always 0 to
   facilitate this.
 - Support shared locking by tracking individual lock instances and
   statistics in the per-thread per-instance lock_profile_object.
 - Make the lock profiling hash table a per-cpu singly linked list with a
   per-cpu static lock_prof allocator.  This removes the need for an array
   of spinlocks and reduces cache contention between cores.
 - Use a seperate hash for spinlocks and other locks so that only a
   critical_enter() is required and not a spinlock_enter() to modify the
   per-cpu tables.
 - Count time spent spinning in the lock statistics.
 - Remove the LOCK_PROFILE_SHARED option as it is always supported now.
 - Specifically drop and release the scheduler locks in both schedulers
   since we track owners now.

In collaboration with:	Kip Macy
Sponsored by:	Nokia

1 files changed, 6 insertions, 1 deletions

diff --git a/sys/kern/sched_4bsd.c b/sys/kern/sched_4bsd.c
index f6e702e..e1e5c91 100644
--- a/sys/kern/sched_4bsd.c
+++ b/sys/kern/sched_4bsd.c
@@ -878,9 +878,11 @@ sched_switch(struct thread *td, struct thread *newtd, int flags)
 		if (PMC_PROC_IS_USING_PMCS(td->td_proc))
 			PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_OUT);
 #endif
-
                 /* I feel sleepy */
+		lock_profile_release_lock(&sched_lock.lock_object);
 		cpu_switch(td, newtd, td->td_lock);
+		lock_profile_obtain_lock_success(&sched_lock.lock_object,
+		    0, 0, __FILE__, __LINE__);
 		/*
 		 * Where am I?  What year is it?
 		 * We are in the same thread that went to sleep above,
@@ -1375,6 +1377,7 @@ sched_throw(struct thread *td)
 		mtx_lock_spin(&sched_lock);
 		spinlock_exit();
 	} else {
+		lock_profile_release_lock(&sched_lock.lock_object);
 		MPASS(td->td_lock == &sched_lock);
 	}
 	mtx_assert(&sched_lock, MA_OWNED);
@@ -1394,6 +1397,8 @@ sched_fork_exit(struct thread *td)
 	 */
 	td->td_oncpu = PCPU_GET(cpuid);
 	sched_lock.mtx_lock = (uintptr_t)td;
+	lock_profile_obtain_lock_success(&sched_lock.lock_object,
+	    0, 0, __FILE__, __LINE__);
 	THREAD_LOCK_ASSERT(td, MA_OWNED | MA_NOTRECURSED);
 }